Did not touch MT 5GHz wireless for a while now as we move to other gear in this band. But there are still some APs around running nv2.
Tried to update an AP with 3 CPEs using nv2. Now I see lower fluctuating speeds. Using plain 802.11ac seems to do better.

So all who stayed with MT Wireless. What is the best WISP protocol to use now, what settings and ROS-Version.

I know this is a late reply but settings i use is nv2 tdma=2ms mode=dynamic downlink downlink ratio=70 Queue count = 8 qos=frame priority. Umpdu Priorities 0 and 7 enable.

Queue count and qos im still testing as I have not made time to test i properly.
Also havent put proper magle rules for the frame priority yes.

NV2 works well for me on 20Mghz channels long distance and so on.
802.11 sees alot of disconnects even though it seems to give better ping times to clients.
Clients need to be below 5km with good signals for 802.11 to work great.

Still optimizing my network to work 20/40/80 better for sector(p2mp) use.

Just for info and maybe get more ideas from your post.

My settings I currently use is as follows maybe some one does something different or can spot a mistake from my side:

Band 5Ghz-A/N/AC
20Mhz
scan list: default
Skip dfs:disable
Wireless Protocol:nv2
Interworking Profile:disabled
Frequency Mode: superchannel
Country:According to country
Installation any
Antenna gain: 0
Bridge Mode:enabled.
Vlan Mode : no tag
Vlan ID:1

Max station Count:30
Client side Hw. :Protection rts cts (seems to have little bit of a increase in bandwidth for clients)
Hw. Retries 4
Adaptive Noise Immunity: ap and client mode and on client cpe client mode enabled

Data rates:
Supported and basic rates only 24mbps and 36mbps selected and vht support MCS alls set to none. (reason is most of our devices is still N protocol)

HT
All chains selected
AMSDU:8192
AMSDU Threshold:8192
Guard Interval :any
AMPDU Priorities: 0 and 7 selected
HT Supported MCS and Basics : set toe MCS10,11 and 12 in most cases 10 and 11 for best ccq

WDS disabled

Nstreme
Enable poling selected
Disable CSMA
Framer :"none
Framer Limit:3200

NV2.
TDMA Period SIze:either 2ms of 3ms
Cell radius. Just above the furthest client
Mode: Dynamic downlink
Downlink Ratio:70
Queue count: 8
Qos: frame priority

Seems as if the Sector bottlenecks round about 35-45mbps.
This might be because of the 20mhz channel or the mcs rates.

Any thoughts will be welcome.
Mostly try to use symmetrical horns from ALG and netmetals for sectors.
Router OS version is on 6.49.6 stable

Thanks for your time